Human adenovirus 36 (HAdV-D36) is the only currently known infectious agent capable of promoting obesity in humans and animals, but the effects on the embryonated chicken egg (ECE) have not been described yet. In our study, we used ECEs as a model of a dynamically developing organism. The allantoic cavity and the yolk sack of ECEs was inoculated with HAdV-D36 to simulate the different routes of infection. Each day, a part of the embryos was weighed and histologically examined and compared to the controls to analyze pathological changes induced by the virus. Our study confirmed a significant increase in the ECEs body weight; however, this process was not caused by adipose tissue development, but increased cell proliferation of all tissues. We suggest that HAdV-D36 must affect the developing organisms via another mechanism inducing enhanced the ECEs growth.